KR20190047169A - Display apparatus and method of fabricating the same - Google Patents

Abstract

Provided are a display device and a manufacturing method of the display device. The display device comprises: a first insulating substrate and a second insulating substrate facing each other, and separately including a pixel region and a pixel boundary; a column spacer disposed on the second insulating substrate; and a common electrode disposed on the second insulating substrate, at least partially covering the column spacer, and including a conductive polymer. Therefore, an objective of the present invention is to provide the display device with improved external light reflection.

Description

DISPLAY APPARATUS AND METHOD OF MANUFACTURING THE SAME

The present invention relates to a display device and a method of manufacturing the same.

Liquid crystal display devices are being applied not only to TVs, monitors, and laptops but also to various devices such as mobile phones, PDAs, and smart phones. A liquid crystal display displays an image by interposing a liquid crystal layer between a lower substrate and an upper substrate and adjusting the transmittance by controlling the orientation angle of the liquid crystal. A column spacer is disposed on the upper substrate to maintain the cell gap.

The alignment angle of the liquid crystal is controlled by an electric field. The liquid crystal display device includes a pixel electrode and a common electrode as electric field generating electrodes. Usually, the pixel electrode is provided on the lower substrate, and the common electrode is provided on the upper substrate.

The common electrode is made of a transparent material so that it basically transmits light, but on the other hand it can reflect some light at the optical interface. Since the common electrode is located on the display surface side, it may cause reflection of external light when exposed to external light, thereby deteriorating display quality. ITO, which is widely used as a common electrode, has a refractive index of 1.8 to 1.9, which limits the reduction of the reflectance.

SUMMARY OF THE INVENTION An object of the present invention is to provide a display device with improved external light reflection.

Another object of the present invention is to provide a method of manufacturing a display device with improved external light reflection.

The problems of the present invention are not limited to the above-mentioned problems, and other technical subjects not mentioned can be clearly understood by those skilled in the art from the following description.

According to an embodiment of the present invention, there is provided a display device comprising: a first insulating substrate and a second insulating substrate which are opposed to each other and which each include a pixel region and a pixel boundary, a column spacer disposed on the second insulating substrate, And a common electrode disposed on the second insulating substrate and at least partially covering the column spacer, the common electrode including a conductive polymer.

The column spacer may be located on the pixel boundary of the second insulating substrate.

And a black matrix disposed on the pixel boundary of the second insulating substrate, wherein the column spacer may be disposed on the black matrix.

The common electrode may be disposed at the pixel region of the second insulating substrate and at the end of the column spacer and the thickness of the common electrode on the pixel region may be thicker than the thickness of the common electrode on the end of the column spacer.

Wherein the column spacer includes a main column spacer and a sub column spacer having a height smaller than that of the main column spacer, wherein a thickness of the common electrode on an end portion of the main column spacer is smaller than a thickness of the common electrode on an end portion of the sub column spacer .

The common electrode exposes an upper end of the sidewall of the column spacer, and the common electrode disposed on the end of the column spacer may be a floating electrode separated from the common electrode on the pixel region.

The common electrode covers the bottom of the sidewall of the column spacer, and exposes the end of the column spacer and the top of the sidewall.

And a pixel electrode disposed on the pixel region on the first insulating substrate and including a transparent conductive oxide material.

The reflectance of the common electrode may be lower than that of the pixel electrode.

The common electrode may be disposed on the pixel region of the second insulating substrate, and the common electrode on the pixel region may be thicker than the pixel electrode.

The refractive index of the common electrode may be 1.5 or less.

The reflectance of the common electrode may be 1.7% or less, the sheet resistance may be 150 Ω / □ or less, and the transmittance may be 88% or more.

The thickness of the common electrode may be 100 nm to 2000 nm.

The common electrode may include a PEDOT: PSS film.

According to another aspect of the present invention, there is provided a method of manufacturing a display device including forming a column spacer on an insulating substrate, forming a composition layer including a conductive polymer and a solvent on the insulating substrate on which the column spacer is formed And removing the solvent to form a common electrode including the conductive polymer.

The step of removing the solvent may include a drying and baking step.

The step of forming the column spacer may include applying organic material, and exposing and developing using a mask.

The column spacer includes a main column spacer and a sub column spacer having a height smaller than the main column spacer, and the mask may include a slit mask or a halftone mask.

The conductive polymer may include PEDOT: PSS.

The composition layer may be coated to a thickness such that all the column spacers are submerged.

The details of other embodiments are included in the detailed description and drawings.

According to the display device of one embodiment, since the conductive polymer material having a relatively low refractive index is used as the common electrode, the reflection of external light can be reduced. In addition, since the common electrode is formed by a method such as slit coating, the process cost can be reduced.

According to the method of manufacturing a display device according to an embodiment, since the column spacer forming step is completed before the common electrode forming step, the conductive polymer can be prevented from being exposed to the developer of the column spacer in advance.

Effects according to the embodiments are not limited by the contents exemplified above, and more various effects are included in the specification.

1 is a plan view of a display device according to an embodiment.
2 is a cross-sectional view of a display device according to an embodiment.
3 is a cross-sectional view of a thin film transistor substrate according to an embodiment.
4 is a schematic cross-sectional view illustrating a pixel electrode and a common electrode of a display device according to an embodiment.
5 is a cross-sectional view of an upper substrate of a display device according to an embodiment.
FIGS. 6 to 8 are cross-sectional views showing steps of a method of manufacturing the upper substrate of FIG.
9 is a cross-sectional view of an upper substrate of a display device according to another embodiment.
10 is a layout diagram of the common electrode of FIG.
11 is a cross-sectional view of an upper substrate of a display device according to yet another embodiment.
12 is a layout diagram of the common electrode of FIG.
13 is a cross-sectional view of an upper substrate of a display device according to yet another embodiment.
14 is a cross-sectional view of an upper substrate of a display device according to another embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

It is to be understood that elements or layers are referred to as " on " of other elements or layers, including all other elements or layers intervening directly or intervening other elements. Like reference numerals refer to like elements throughout the specification.

Although the first, second, etc. are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, it goes without saying that the first component mentioned below may be the second component within the technical scope of the present invention.

Hereinafter, embodiments will be described with reference to the accompanying drawings.

1 is a plan view of a display device according to an embodiment.

Referring to Fig. 1, the display device 10 includes a plurality of pixels PX. The plurality of pixels PX may be arranged in a matrix form. The plurality of pixels PX may be divided into a plurality of color pixels indicating a specific color. For example, the plurality of pixels PX may include a plurality of red pixels, a plurality of green pixels, and a plurality of blue pixels. The red, green, and blue pixels may be alternately arranged.

A black matrix 220 is disposed at the boundary of each pixel PX to prevent transmission of light. The black matrix 220 may have a lattice shape.

The display device 10 may include a lower substrate 100 and an upper substrate 200 facing each other and may include a column spacer 230 serving to maintain an interval therebetween. The column spacers 230 may be formed on the upper substrate 200 or the lower substrate 100.

The column spacer 230 may be located at the boundary of the pixel. The column spacer 230 may overlap the black matrix 220. In one embodiment, the column spacer 230 may be disposed on a crossing area CSR where the column direction extension part REP and the column direction extension part CEP of the black matrix 220 intersect. However, the present invention is not limited thereto, and it may be arranged on the row direction extending portion REP of the black matrix 220 or the column direction extending portion CEP.

The column spacer 230 may include a main column spacer 231 and a sub column spacer 232. The main column spacer 231 maintains the gap between the upper substrate 200 and the lower substrate 100 under a normal unpressurized condition and the sub column spacer 232 maintains the spacing between the upper substrate 200 and the lower substrate 100 ) In the direction of the arrow. The height of the end portion of the sub column spacer 232 may be smaller than the height of the end portion of the main column spacer 231. When the column spacer 230 is formed on the upper substrate 200, the end of the main column spacer 231 comes into contact with the lower substrate 100 in the unpressurized state, but the end of the sub column spacer 232 is in contact with the lower substrate 100).

The column spacer 230 need not be arranged for every crossing region (CSR). For example, one per three crossing regions (CSR) can be arranged and various other arrangements are possible. The arrangement density of the main column spacer 231 and the sub column spacer 232 may be the same, but is not limited thereto.

2 is a cross-sectional view of a display device according to an embodiment. In FIG. 2, the main column spacer 231 and the sub column spacer 232 are disposed on one side and the other side, respectively, of one pixel for convenience of explanation.

Referring to FIG. 2, the display device 10 includes a lower substrate 100 and an upper substrate 200 facing each other. A liquid crystal layer 300 is disposed between the lower substrate 100 and the upper substrate 200. Although not shown in the drawing, an alignment layer may be disposed on the lower substrate 100 and the upper substrate 200, which are in contact with the liquid crystal layer 300.

The lower substrate 100 may include a first insulating substrate 110, a color filter 120, and a pixel electrode 140. The first insulating substrate 110 may be made of a transparent material such as glass or quartz.

The color filter 120 and the pixel electrode 140 may be disposed on the first insulating substrate 110. The color filter 120 may be disposed between the first insulating substrate 110 and the pixel electrode 140. The color filter 120 and the pixel electrode 140 may be disposed for each pixel. The color filter 120 may include a red color filter 120R, a blue color filter 120B, and a green color filter 120G.

The color filters 120 of neighboring pixels may be partially overlapping. The color filter 120 can cause a step difference, and the level difference can be solved by disposing the planarization film 130 on the color filter 120. The pixel electrode 140 may be disposed on the planarization layer 130.

The pixel electrode 140 is divided into pixels, and a pixel voltage can be applied by a separate switching element. The switching element may comprise a thin film transistor. The structure of an exemplary lower substrate 100 having thin film transistors is shown in FIG. Hereinafter, the term " thin film transistor substrate " refers to a substrate comprising thin film transistors.

3 is a cross-sectional view of a thin film transistor substrate according to an embodiment. Referring to FIGS. 1 to 3, a gate electrode 121 is disposed on a first insulating substrate 110. The gate electrode 121 is connected to the gate line extending in the row direction along the boundary of the pixel. The gate line may overlap the row direction extension portion REP of the black matrix 220. [ A gate insulating film 122 is disposed on the gate electrode 121 and a semiconductor layer 123 is disposed on the gate insulating film 122. The semiconductor layer 123 may include a silicon semiconductor such as amorphous silicon or polycrystalline silicon, or an oxide semiconductor such as IGZO (Indium Gallium Zinc Oxide). A source electrode 124 and a drain electrode 125 spaced apart from the source electrode 124 are disposed on the semiconductor layer 123. The source electrode 124 is connected to the data line extending in the column direction along the boundary of the pixel. The data lines may overlap the column-direction extension (CEP) of the black matrix (220).

The gate electrode 121, the source electrode 124, and the drain electrode 125 described above constitute three terminals of the thin film transistor. The semiconductor layer becomes a channel of the thin film transistor. The thin film transistor may overlap the intersection region CSR of the black matrix 220. [

A passivation film 126 is disposed on the source electrode 124 and the drain electrode 125, and a color filter 120 is disposed thereon. A planarization film 130 is disposed on the color filter 120, and a pixel electrode 140 is disposed thereon. The pixel electrode 140 is electrically connected to the drain electrode 125 through the contact hole 127 that exposes the drain electrode 125 through the planarization layer 130, the color filter 120, and the passivation layer 126 . The pixel electrode 140 may be formed of a transparent conductive oxide material such as ITO or IZO.

Although a thin film transistor substrate including a bottom gate type thin film transistor is illustrated in FIG. 3, a top gate type thin film transistor may also be applied.

Referring again to FIG. 2, the upper substrate 200 includes a second insulating substrate 210, a black matrix 220, a column spacer 230, and a common electrode 240.

The second insulating substrate 210 may be made of a transparent material such as glass or quartz. A black matrix 220 is disposed on the second insulating substrate 210. The black matrix 220 may be disposed along the boundary of the pixel as described above. The black matrix 220 may be formed of an organic material including a photosensitive material, a organic material, or an opaque inorganic material such as a metal.

The column spacers 230 may be disposed on the black matrix 220. The column spacer 230 may be located on the pixel boundary. The column spacer 230 may be made of an organic material including a photosensitive material. The column spacer 230 may be made of a transparent material, but is not limited thereto. The main column spacer 231 and the sub column spacer 232 may be simultaneously formed through a single mask process using the same material.

A common electrode 240 is disposed on the column spacer 230. The common electrode 240 faces the pixel electrode 140. The common electrode 240 is disposed over a plurality of pixels. A common voltage may be applied to the common electrode 240. The pixel voltage of the pixel electrode 140 and the common voltage of the common electrode 240 form an electric field in the liquid crystal layer 300 located therebetween. The pixel electrode 140 and the common electrode 240 may form a liquid crystal capacitor having the liquid crystal layer 300 as a dielectric.

The common electrode 240 may be a current-collecting electrode connected in series. The common electrode 240 may serve as a passage for discharging static electricity when the display device 10 generates static electricity.

The common electrode 240 may be disposed not only on the pixel region of the second insulating substrate 210 but also on the boundary of the pixel and may also be disposed on the column spacer 230 to cover the side wall and the end portion of the column spacer 230. An electric field may be formed between the common electrode 240 and the pixel electrode 140 on the column spacer 230 as the common electrode 240 covers the column spacer 230. The direction of the common electrode 240 on the sidewall of the column spacer 230 is different from that of the common electrode 240 on the pixel region. Accordingly, although the alignment of the liquid crystal 301 is changed in the vicinity of the sidewall of the column spacer 230 to change the transmittance, since the black matrix 220 covers the position, the leakage of light at the corresponding position can be minimized .

The common electrode 240 may be made of a transparent conductive material. The common electrode 240 may include a conductive polymer material in a transparent conductive material. Examples of the conductive polymer material include, but are not limited to, polyethylene dioxythiophene (PEDOT), polyethylene dioxythiophene polystyrene sulfonate (PEDOT: PSS), poly (3-alkyl) thiophene (3-alkyl) thiophene, P3AT, poly (3-hexyl) thiophene, P3HT, polyaniline, polyacetylene, polyazulene, It is preferable to use one or more selected from the group consisting of polyisothianaphthalene, polyisothianaphthene, polythienylenevinylene, polythiophene, polyphenylene, polyphenylene sulfide, Polyparaphenylene, polyparaphenylene vinylene, polyfuran, polypyrrole, polyheptadiyne, and the like. In an exemplary embodiment, the common electrode 240 may comprise PEDOT: PSS. PEDOT: PSS which is one of the conductive polymer materials satisfies the transmittance and conductivity required by the common electrode 240, but has a low refractive index, thereby reducing external light reflection. Reference is made to Figure 4 for a detailed description of this.

4 is a schematic cross-sectional view illustrating a pixel electrode and a common electrode of a display device according to an embodiment.

4 illustrates a case where ITO is used for the pixel electrode 140 and PEDOT: PSS is used for the common electrode 240. FIG. As shown in FIG. 4, the common electrode 240 including PEDOT / PSS may have a thicker average thickness and a lower refractive index than the pixel electrode 140 including ITO.

The common electrode 240 is disposed on the upper substrate 200. When external light is incident, external light may be reflected at the interface. The external light reflectance becomes larger as the refractive index of the common electrode 240 becomes higher. For example, when ITO having a refractive index of 1.8 to 1.9 is applied to the common electrode 240 at about 50 nm, the reflectance is close to 4.47%. If the thickness of the ITO is increased up to 135 nm, the reflectance can be lowered to 1.7%. In this case, however, the reduction of the reflectance is also limited. In addition, since ITO is usually formed by sputtering deposition, it takes a lot of processing time to increase the thickness, and material consumption may increase, which may increase the process cost.

On the other hand, the PEDOT: PSS film may have a refractive index of about 1.5 or less, which is a lower refractive index than the ITO film. Since the PEDOT: PSS film can be formed by a method such as slit coating, the process cost can be reduced even if it is thicker than ITO, for example, about 100 to 2000 nm. In such a thickness range, the PEDOT / PSS film has a sheet resistance of less than 150? / ?, and the reflectance can be less than 1.7% while having a transmittance of 88% or more. The reflectance of the PEDOT / PSS film may preferably be 1.5% or less.

The PEDOT: PSS material was slit coated on a 18.2 inch glass substrate to investigate the reflectivity of the PEDOT: PSS film. Thereafter, the film was baked at 230 DEG C for 20 minutes to form a PEDOT: PSS film having a thickness of 680 nm. The physical properties of the formed PEDOT: PSS film were measured. As a result, the sheet resistance was found to be 116 OMEGA / & squ &, the transmittance was 89%, and the reflectance was 1.4%, which exhibited a transparent conductive property equivalent to that of ITO film .

4, ITO is applied to the pixel electrode 140. However, the pixel electrode 140 may also be formed of a conductive polymer material such as PEDOT: PSS.

5 is a cross-sectional view of an upper substrate of a display device according to an embodiment. For the convenience of explanation, FIG. 5 is reversed from FIG. 2 and the vertical direction.

Referring to FIGS. 2 and 5, the thickness of the common electrode 240 may vary depending on the position. The common electrode 240 may have a thickness d1 in a portion opposed to the pixel electrode 140, that is, in a pixel region, which is greater than a thickness of a portion where the column spacer 230 is located. The thickness d4 of the common electrode 240 located on the end of the main column spacer 231 may be smaller than the thickness d3 of the common electrode 240 located on the end of the sub column spacer 232. [ The common electrode 240 is disposed on the black matrix 220 in the region where the column spacer 230 is not disposed. The thickness d2 of the common electrode 240 located on the black matrix 220 may be smaller than the thickness d1 in the pixel region and larger than the thicknesses d3 and d4 of the end portions of the column spacer 230. [

The difference in the thickness of the common electrode 240 is related to the height of the structure based on the second insulating substrate 210. The thickness of the common electrode 240 decreases as the height of the lower structure in which the common electrode 240 is formed increases. That is, the common electrode 240 has the first thickest thickness d1 in the pixel region closest to the surface of the second insulating substrate 210 and the second thickness d2 on the black matrix 220 Column spacer 233 having a third thickness d3 at the end of the sub-column spacer 232 that is greater than the black matrix 220 and greater than the sub-column spacer 232 at the end of the main column spacer 231, (d4). Here, the thickness is in the order of the first thickness d1, the second thickness d2, the third thickness d3, and the fourth thickness d4.

A method of forming the common electrode 240 having a different thickness for each position as described above will be described with reference to FIGS. 6 to 8. FIG. FIGS. 6 to 8 are cross-sectional views illustrating steps of the method for manufacturing the upper substrate 200 of FIG.

Referring to FIG. 6, a black matrix 220 is formed on a second insulating substrate 210. For example, an organic material including a photosensitive material may be applied, exposed using a mask, and then developed to form a black matrix 220 having a specific pattern.

Referring to FIG. 7, a column spacer 230 is formed. For example, organic materials are coated on the second insulating substrate 210 on which the black matrix 220 is formed. Thereafter, exposure is performed using a mask. A slit mask or a halftone mask can be used as a mask in order to simultaneously form the column spacers 230 having different heights by a single process. Subsequently, the main column spacer 231 and the sub column spacer 232 having different heights can be formed through the developing process.

The above-described column spacer 230 is formed before the common electrode 240 is formed. Generally, the conductive polymer is vulnerable to the developing solution of the column spacer 230. Accordingly, if the common electrode 240 is formed first and then the column spacer 230 is formed, the common electrode 240 including the conductive polymer is exposed to the developer of the column spacer 230 to increase the sheet resistance value There is a concern. When the column spacer 230 is formed first and the common electrode 240 is formed as in the present embodiment, the conductive polymer can be prevented from being exposed to the developer of the column spacer 230 in advance.

Referring to FIG. 8, a composition including a conductive polymer is coated on a second insulating substrate 210 on which a column spacer 230 is formed to form a composition layer 240p. The composition further comprises a solvent as well as a conductive polymer which is solid. Since the solvent is removed in the subsequent process and only the solids are left, the thickness of the composition is coated to a much thicker thickness than the target common electrode 240. In one embodiment, the composition may be coated to a thickness such that all of the column spacers 230 are submerged.

On the other hand, since the composition is in a liquid state, the surface of the coated composition layer 240p may be flat without reflecting the surface shape of the lower structure. Accordingly, the thickness (vertical thickness) A sixth thickness d6 on the black matrix 220 and a seventh thickness d7 on the subcolumn spacers 232 and a third thickness d7 on the sub column spacer 232. In other words, And the eighth thickness d8 on the column spacer 231. The thickness of the column spacer 231 may be selected from the group consisting of a fifth thickness d5, a sixth thickness d6, a seventh thickness d7, to be.

Thereafter, the solvent of the composition is removed while drying and baking, and the conductive polymer, which is a solid component, remains on the second insulating substrate 210, so that the common electrode 240 as shown in FIG. 5 can be formed. The larger the thickness of the composition layer 240p is, the larger the amount of the solid component is, so that a thicker layer can be formed. The thickness of the common electrode 240 is the largest in the pixel region having the layer thickness of the thickest composition layer 240p as described above and the thickness of the common electrode 240 on the black matrix 220, The thickness of the common electrode 240 becomes smaller in the order of the ends of the main column spacer 231.

The difference in the thickness of the common electrode 240 with respect to the position will be larger as the step height of the lower structure is larger. The position where the step of the substructure is largest may be between the column spacer 230 and the black matrix 220. In this case, the difference between the third thickness d3 and the second thickness d2 and the difference between the fourth thickness d4 and the second thickness are larger than the difference between the first thickness d1 and the second thickness d2 have.

Although the thickness d1 of the common electrode 240 on the pixel region is larger than that of the pixel electrode 140, the thicknesses d2, d3, and d4 of the common electrode 240 at other positions are smaller than the thickness d2, It may be large, it may be the same, or it may be small. For example, the fourth thickness d4 of the common electrode 240 on the main column spacer 231 having the smallest thickness among the common electrodes 240 may be larger than the pixel electrode 140. In this case, the common electrode 240 is thicker than the pixel electrode 140 at all positions. As another example, the fourth thickness d4 of the common electrode 240 on the main column spacer 231 may be less than or equal to the pixel electrode 140. Further, the third thickness d3 of the common electrode 240 on the sub-column spacer 232 may be smaller than or equal to the pixel electrode 140. [

Hereinafter, other embodiments will be described. In the following embodiments, the same components as those described in the previous embodiment will be referred to by the same reference numerals, and duplicate descriptions will be omitted or simplified.

9 is a cross-sectional view of an upper substrate of a display device according to another embodiment. 10 is a layout diagram of the common electrode of FIG.

9 and 10, the upper substrate 201 of the display device according to the present embodiment is configured such that the common electrode 241 does not completely cover the column spacer 230 but exposes a part of the sidewall of the column spacer 230 Which is different from the embodiment of Fig.

Specifically, the common electrode 241 is disposed on the end of the column spacer 230, but the upper end of the sidewall of the column spacer 230 is exposed without being covered by the common electrode 241. In other words, the thickness of the common electrode 241 on the upper side of the sidewall of the column spacer 230 becomes zero. The lower end of the side wall of the column spacer 230 is covered by the common electrode 241. The height of the common electrode 240 on the lower side wall of the main column spacer 231 from the surface of the second insulating substrate 210 and the height of the common electrode 240 on the lower side wall of the sub column spacer 232 may be substantially the same.

The common electrode 241 on the lower side of the sidewall of the column spacer 230, which appears to be separated in the sectional view of Fig. 9, is actually connected to each other surrounding the end of the column spacer 230 as shown in the plan view of Fig.

The common electrode 241 on the end of the column spacer 230 can be separated from the common electrode 241 on the pixel region. As a result, the common electrode 241 on the end of the column spacer 230 can be a floating electrode. The common electrode 241 may include a ring-shaped open portion 241R around the end of the column spacer 230. [

The thickness of the common electrode 241 on the end of the main column spacer 231 may be smaller than the thickness of the common electrode 241 on the end of the sub column spacer 232, but is not limited thereto.

The shape of the common electrode 241 as in the present embodiment is such that when the composition layer is coated on the upper substrate 201 of the display device and dried and baked, This is due to the fact that it has flowed down and remained non-residing.

11 is a cross-sectional view of an upper substrate of a display device according to yet another embodiment. 12 is a layout diagram of the common electrode of FIG.

11 and 12, the upper substrate 202 of the display device according to the present embodiment is formed such that the common electrode 242 is formed not only on the upper end of the side wall of the column spacer 230 but also on the end portion thereof, The present embodiment differs from the embodiment of Figs. A common electrode hole 242H may be formed at each end of the column spacer 230 as shown in FIG. 12 on a plan view, as the common electrode 242 is formed at the end of the column spacer 230.

The shape of the common electrode 242 as in this embodiment can be formed when the coating height of the composition layer is smaller than the height of the column spacer 230 in the manufacturing step of the upper substrate 202 of the display device. That is, when the composition layer is coated to such an extent that the end of the column spacer 230 and the upper portion of the side wall are not immersed, the common electrode 242 formed by drying and baking is also formed on the end of the column spacer 230 and the upper end of the side wall .

13 is a cross-sectional view of an upper substrate of a display device according to yet another embodiment.

13, the upper substrate 203 of the display according to the present embodiment includes the overcoat layer 250 between the black matrix 220 and the column spacer 230, There is a difference. The overcoat layer 250 covers the black matrix 220 and the column spacers 230 are disposed on the overcoat layer 250. In addition, the common electrode 243 is disposed on the overcoat layer 250 and covers the column spacer 230.

The overcoat layer 250 is made of an organic insulating material such as polyimide, photoacrylic, or the like, and can perform a planarization function. The stepped portion by the black matrix 220 can be eliminated by the overcoat layer 250. Therefore, in the case of this embodiment, the difference in thickness of the common electrode 243 due to the step of the black matrix 220 discussed in the embodiment of Fig. 5 may not occur.

14 is a cross-sectional view of an upper substrate of a display device according to another embodiment.

Referring to Fig. 14, the display device according to the present embodiment is different from the embodiment of Fig. 13 in that the upper substrate 204 includes a color filter.

Specifically, the black matrix 220 may be disposed on the second insulating substrate 210, and the color filters 260R, 260B, and 260G may be disposed thereon. An overcoat layer 250 is disposed on the color filters 260R, 260B, and 260G, and a column spacer 230 is disposed thereon. The common electrode 243 is disposed on the overcoat layer 250 and is arranged to cover the column spacer 230.

14 illustrates that the color filters 260R, 260B, and 260G may be formed on the upper substrate 200 rather than the lower substrate 100. FIG. When the color filters 260R, 260B and 260G are disposed on the upper substrate 200, the color filter 120 of the lower substrate 100 shown in FIG. 2 may be omitted.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

10: Display device
100: Lower substrate
200: upper substrate
230: Column spacer
240: common electrode

Claims (20)

A first insulating substrate and a second insulating substrate facing each other and including a pixel region and a pixel boundary;
A column spacer disposed on the second insulating substrate; And
And a common electrode disposed on the second insulating substrate and at least partially covering the column spacer, the common electrode including a conductive polymer. The method according to claim 1,
And the column spacer is located on the pixel boundary of the second insulating substrate. 3. The method of claim 2,
Further comprising a black matrix disposed on the pixel boundary of the second insulating substrate,
Wherein the column spacer is disposed on the black matrix. 3. The method of claim 2,
The common electrode is disposed at the pixel region of the second insulating substrate and at the end of the column spacer,
Wherein a thickness of the common electrode on the pixel region is thicker than a thickness of the common electrode on an end portion of the column spacer. 5. The method of claim 4,
Wherein the column spacer includes a main column spacer and a sub column spacer having a height smaller than the main column spacer,
And the thickness of the common electrode on the end of the main column spacer is smaller than the thickness of the common electrode on the end of the subcolumn spacer. 5. The method of claim 4,
The common electrode exposes an upper end of a sidewall of the column spacer,
And a common electrode disposed on an end of the column spacer is a floating electrode separated from the common electrode on the pixel region. 3. The method of claim 2,
Wherein the common electrode covers the lower end of the sidewall of the column spacer and exposes the end of the column spacer and the upper end of the sidewall. 8. The method of claim 7,
And a pixel electrode disposed in the pixel region on the first insulating substrate and including a transparent conductive oxide material. 9. The method of claim 8,
Wherein the reflectance of the common electrode is lower than the reflectivity of the pixel electrode. 9. The method of claim 8,
The common electrode is disposed on the pixel region of the second insulating substrate,
Wherein the common electrode on the pixel region is thicker than the pixel electrode. The method according to claim 1,
And the refractive index of the common electrode is 1.5 or less. 12. The method of claim 11,
The reflectance of the common electrode is 1.7% or less, the sheet resistance is 150? /? Or less, and the transmittance is 88% or more. The method according to claim 1,
Wherein the common electrode has a thickness of 100 nm to 2000 nm. The method according to claim 1,
Wherein the common electrode comprises a PEDOT: PSS film. Forming a column spacer on the insulating substrate;
Forming a composition layer comprising a conductive polymer and a solvent on an insulating substrate on which the column spacer is formed; And
And removing the solvent to form a common electrode including the conductive polymer. 16. The method of claim 15,
Wherein the step of removing the solvent includes a drying and a baking step. 17. The method of claim 16,
Wherein forming the column spacer comprises applying an organic material, and
And exposing and developing using a mask. 18. The method of claim 17,
Wherein the column spacer includes a main column spacer and a sub column spacer having a height smaller than the main column spacer,
Wherein the mask comprises a slit mask or a halftone mask. 16. The method of claim 15,
Wherein the conductive polymer comprises PEDOT: PSS. 16. The method of claim 15,
Wherein the composition layer is coated to a thickness at which the column spacer is all submerged.

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